This is best free online unit conversion tool and calculator so you convert centimeter, feet, inches, kilometer, league, meter, microinch, mile, millimeters, yard into each other. Almost all length units can be converted using this tool. The millimeter is a unit of length which corresponds to one thousandth of a meter. Inches are widely used in the United States, United Kingdom and Canada. In those countries personal heights are usually expressed in inches and feet. 1 foot is equivalent to 12 inches and 36 inches correspond to one yard.